International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 10 Issue: 10 | Oct 2023
p-ISSN: 2395-0072
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Impact of Wood Ash, Silica Fume, and Calcium Oxide on the Compressive Strength of Mortar Choolwe Kamanga 1Student, School of Civil Engineering and Architecture, Anhui University of Science and Technology
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as coal-fired power facilities close throughout the world, less fly ash is available. An industrial by-product of woodfired facilities, wood ash is created as an alternative to fly ash [3].
Abstract - Ordinary Portland cement is the most common
type of cement used around the world, and it is used as a binding material in the production of mortar and concrete. However, during the production of ordinary Portland cement, there have been substantial amount of CO 2 emissions. Therefore, supplementary cementitious materials have been used to minimize the production of ordinary Portland cement, reducing pollution due to CO2, preserving limestone, and also helping to save energy used during cement production. Wood ash and silica fume have been considered as some of the supplementary cementitious materials used. These materials are by-products from other processes or natural materials, and they are used to improve the workability, durability, and strength of the mortar and concrete. In this study, a fixed amount of wood ash and silica fume was used to replace the cement content of the mortar, and their influence on the compressive strength of the mortar was investigated. The compressive strength of the mortar was evaluated and measured at the curing periods of 7 and 28 days. The test results show that the addition of silica fume increased the compressive strength of the mortar, while the addition of wood ash showed a gradual increase in compressive strength. However, when calcium oxide (CaO) was added to the mortar containing wood ash, it showed an increase in compressive strength over a length of time. The study concluded that the use of wood ash and silica fume improves strength over time and is therefore recommended as an additional cementitious material.
Wood ash is produced at a rate of roughly 4600 million tons per year. It is predicted that it will be challenging to locate the necessary landfills due to the growth in the production of this waste. However, the disposal of fine and light wood ash would result in serious contamination of the air, water, and soil, which may have an adverse effect on human health and the ecosystem. As a result, the wood ash has been recycled and used as an additional cementitious material in mortar and concrete. It has been viewed as a way to dispose of waste in large quantities without affecting the environment [3][4]. Silica fume is one of the pozzolanic materials with a high content of amorphous silicon dioxide, ranging from 85% to 98%, in the form of very fine spherical particles averaging diameters of about 0.1 to 0.5 microns. It is mainly used in the production of mortar and concrete [5]. Silica has become useful in the production of high-strength concrete because of its ability to increase the bond between cement paste and aggregate by making the interfacial zone denser. It increases the mechanical strength of concrete and mortar due to its pozzolanic nature [6]. In a study conducted by Antonia and Lucky Chandra, 0–10% of silica fume, 0–30% of fly ash, and 0– 15% of calcium carbonate were used as cement content, respectively. They came to the conclusion that the use of silica fume reduced the workability of fresh mortar, necessitating the addition of superplasticizer to increase workability after evaluating the workability and compressive strength of hardened mortar at ages 7, 14, 28, and 58 days. Whereas, at the age of 56 days, they obtained the highest compressive strength when 20% fly ash and 2.5% silica fume were used. However, the use of calcium carbonate content up to 15%, increased the compressive strength of the mortar at the early stage [7]. Therefore, calcium oxide, which is produced when calcium carbonate is heated, was suggested to be used in this study to examine how it can affects the mortar, which contains silica fume and wood ash, respectively.
Key Words: Wood Ash, Silica Fume, Calcium Oxide, Compressive Strength, Mortar
1. INTRODUCTION Wood ash is generated as a by-product of combustion in wood-fired plants, paper mills, and other wood-burning industries. Fly ash, which is produced during the combustion of coal in electricity power plants, can be compared to wood ash [1]. However, since the use of coalfired power plants has been considered dangerous due to the increase in CO2 emissions. According to a study by Hossain Masum [2], switching from coal to a different fuel source could reduce carbon emissions by 43%. The study suggested that the use of wood biomass, such as wood chips and logging, could be the best fuel source, which is more cost-effective and environmentally friendly. For many years, fly ash was used in place of cement to create more durable and affordable building materials. However,
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Herry and Hermawan conducted a study to investigate the influence of calcium oxide doses as an activator on the compressive strength and mechanical characteristics of cement-free mortar containing ground granulated blast furnace slag. In this study, 5%, 15%, and 25% CaO doses were used on the cement-free mortar containing GGBFS, and compressive strength was investigated. The results of
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